Graphics culling;

src/graphics/graphics.c

@@ -50,6 +50,8 @@ void lovrGraphicsReset() {
   lovrGraphicsSetColorMask(1, 1, 1, 1);
   lovrGraphicsSetScissorEnabled(0);
   lovrGraphicsSetLineWidth(1);
+  lovrGraphicsSetCullingEnabled(0);
+  lovrGraphicsSetPolygonWinding(POLYGON_WINDING_COUNTERCLOCKWISE);
 }
 
 void lovrGraphicsClear(int color, int depth) {
@@ -207,6 +209,28 @@ void lovrGraphicsSetLineWidth(float width) {
   glLineWidth(width);
 }
 
+char lovrGraphicsIsCullingEnabled() {
+  return state.isCullingEnabled;
+}
+
+void lovrGraphicsSetCullingEnabled(char isEnabled) {
+  state.isCullingEnabled = isEnabled;
+  if (isEnabled) {
+    glEnable(GL_CULL_FACE);
+  } else {
+    glDisable(GL_CULL_FACE);
+  }
+}
+
+PolygonWinding lovrGraphicsGetPolygonWinding() {
+  return state.polygonWinding;
+}
+
+void lovrGraphicsSetPolygonWinding(PolygonWinding winding) {
+  state.polygonWinding = winding;
+  glFrontFace(winding);
+}
+
 int lovrGraphicsPush() {
   vec_mat4_t* transforms = &state.transforms;
   if (transforms->length >= 64) { return 1; }

src/graphics/graphics.h

@@ -25,6 +25,11 @@ typedef enum {
   DRAW_MODE_LINE
 } DrawMode;
 
+typedef enum {
+  POLYGON_WINDING_CLOCKWISE = GL_CW,
+  POLYGON_WINDING_COUNTERCLOCKWISE = GL_CCW
+} PolygonWinding;
+
 typedef struct {
   Shader* activeShader;
   Shader* defaultShader;
@@ -43,6 +48,8 @@ typedef struct {
   vec_float_t shapeData;
   vec_uint_t shapeIndices;
   float lineWidth;
+  char isCullingEnabled;
+  PolygonWinding polygonWinding;
 } GraphicsState;
 #endif
 
@@ -67,6 +74,10 @@ void lovrGraphicsSetProjection(float near, float far, float fov);
 void lovrGraphicsSetProjectionRaw(mat4 projection);
 float lovrGraphicsGetLineWidth();
 void lovrGraphicsSetLineWidth(float width);
+char lovrGraphicsIsCullingEnabled();
+void lovrGraphicsSetCullingEnabled(char isEnabled);
+PolygonWinding lovrGraphicsGetPolygonWinding();
+void lovrGraphicsSetPolygonWinding(PolygonWinding winding);
 int lovrGraphicsPush();
 int lovrGraphicsPop();
 void lovrGraphicsOrigin();

src/lovr/graphics.c

@@ -22,6 +22,10 @@ const luaL_Reg lovrGraphics[] = {
   { "setProjection", l_lovrGraphicsSetProjection },
   { "getLineWidth", l_lovrGraphicsGetLineWidth },
   { "setLineWidth", l_lovrGraphicsSetLineWidth },
+  { "isCullingEnabled", l_lovrGraphicsIsCullingEnabled },
+  { "setCullingEnabled", l_lovrGraphicsSetCullingEnabled },
+  { "getPolygonWinding", l_lovrGraphicsGetPolygonWinding },
+  { "setPolygonWinding", l_lovrGraphicsSetPolygonWinding },
   { "push", l_lovrGraphicsPush },
   { "pop", l_lovrGraphicsPop },
   { "origin", l_lovrGraphicsOrigin },
@@ -61,6 +65,10 @@ int l_lovrGraphicsInit(lua_State* L) {
   map_set(&DrawModes, "fill", DRAW_MODE_FILL);
   map_set(&DrawModes, "line", DRAW_MODE_LINE);
 
+  map_init(&PolygonWindings);
+  map_set(&PolygonWindings, "clockwise", POLYGON_WINDING_CLOCKWISE);
+  map_set(&PolygonWindings, "counterclockwise", POLYGON_WINDING_COUNTERCLOCKWISE);
+
   lovrGraphicsInit();
   return 1;
 }
@@ -212,6 +220,41 @@ int l_lovrGraphicsSetLineWidth(lua_State* L) {
   return 0;
 }
 
+int l_lovrGraphicsIsCullingEnabled(lua_State* L) {
+  lua_pushboolean(L, lovrGraphicsIsCullingEnabled());
+  return 1;
+}
+
+int l_lovrGraphicsSetCullingEnabled(lua_State* L) {
+  lovrGraphicsSetCullingEnabled(lua_toboolean(L, 1));
+  return 0;
+}
+
+int l_lovrGraphicsGetPolygonWinding(lua_State* L) {
+  switch (lovrGraphicsGetPolygonWinding()) {
+    case POLYGON_WINDING_CLOCKWISE:
+      lua_pushstring(L, "clockwise");
+      return 1;
+
+    case POLYGON_WINDING_COUNTERCLOCKWISE:
+      lua_pushstring(L, "counterclockwise");
+      return 1;
+  }
+
+  return 0;
+}
+
+int l_lovrGraphicsSetPolygonWinding(lua_State* L) {
+  const char* userWinding = luaL_checkstring(L, 1);
+  PolygonWinding* winding = (PolygonWinding*) map_get(&PolygonWindings, userWinding);
+  if (!winding) {
+    return luaL_error(L, "Invalid winding: '%s'", userWinding);
+  }
+
+  lovrGraphicsSetPolygonWinding(*winding);
+  return 0;
+}
+
 int l_lovrGraphicsPush(lua_State* L) {
   if (lovrGraphicsPush()) {
     return luaL_error(L, "Unbalanced matrix stack (more pushes than pops?)");

src/lovr/graphics.h

@@ -6,6 +6,7 @@
 map_int_t BufferDrawModes;
 map_int_t BufferUsages;
 map_int_t DrawModes;
+map_int_t PolygonWindings;
 
 extern const luaL_Reg lovrGraphics[];
 int l_lovrGraphicsInit(lua_State* L);
@@ -25,6 +26,10 @@ int l_lovrGraphicsSetShader(lua_State* L);
 int l_lovrGraphicsSetProjection(lua_State* L);
 int l_lovrGraphicsGetLineWidth(lua_State* L);
 int l_lovrGraphicsSetLineWidth(lua_State* L);
+int l_lovrGraphicsIsCullingEnabled(lua_State* L);
+int l_lovrGraphicsSetCullingEnabled(lua_State* L);
+int l_lovrGraphicsGetPolygonWinding(lua_State* L);
+int l_lovrGraphicsSetPolygonWinding(lua_State* L);
 int l_lovrGraphicsPush(lua_State* L);
 int l_lovrGraphicsPop(lua_State* L);
 int l_lovrGraphicsOrigin(lua_State* L);